WO2019185466A1

WO2019185466A1 - Device for manipulating particles

Info

Publication number: WO2019185466A1
Application number: PCT/EP2019/057202
Authority: WO
Inventors: Matthias HICK; Kevin ECKES; Colin GUILLAUME; Antoine DEBLIRE; Charles-Edouard MOENS DE HASE
Original assignee: Aerosint Sa
Priority date: 2018-03-28
Filing date: 2019-03-22
Publication date: 2019-10-03
Also published as: US20210114296A1; EP3774293A1; BE1026143B1; BE1026143A1; US11273599B2

Abstract

The present application relates to a device (1) for manipulating particles. The device (1) comprises a rotating screen (10) on which a structure (30) of particiles can be formed. According to a first aspect, the device (1) comprises at least one scraper (86, 87) and at least one support element (88, 89) which supports the screen (10) at the scraper (86, 87). According to a second aspect, the device (1) comprises a particle reservoir (80) and a blower which is located inside the screen and under the reservoir (80) and which blows a gas in order to fluidise the particles present in the reservoir (80).

Description

Device for handling particles

Technical area

The present invention relates to a device for manipulating particles. More specifically, the present invention relates to a device for manipulating particles that can be used in 3D printing.

Prior art

It is known to deposit a particle structure on a moving surface to manipulate these particles.

A problem is that the structure on the moving surface may be irregular in time and / or space.

[0004] US2007 / 126157 A1 discloses methods and apparatus for removing finished articles from a powder-based rapid prototyping system. US2004 / 084814 A1 discloses a system for making three-dimensional objects with a non-bonded powder removal device. US2015 / 266241 A1 discloses an additive manufacturing system comprising a planarizer configured to perform solvent assisted planarizations on intermediate construction surfaces of the three-dimensional part.

Summary of the invention

An object of the invention is to provide a device for manipulating particles to obtain a particle structure present on a particularly smooth moving surface. For this purpose, according to a first aspect, the invention proposes a device for handling particles and comprising:

A screen having a first surface on which a particle structure can be formed, the first surface being arranged to be moved to move the particle structure in a direction parallel to the tangent to the first surface; A first scraper located on a first side of the sieve, at a non-zero distance from the first surface, and arranged to scrape the particle structure on a first portion of the sieve, and

A first support member located on a second side of the screen and arranged to support the first portion of the screen, the second side of the screen and the first side of the screen being separated by the screen.

The first scraper can scrape the particles on the screen to obtain a structure having a particularly constant thickness in time and space. The first support member, which is preferred but not necessary in the context of the present invention, allows that the pressure exerted by the first scraper does not deform the sieve.

In addition, if there is an overall strain of the sieve, for example because of a vacuum inside the sieve, it is particularly advantageous to avoid this deformation on the portion of the sieve where scraping takes place because it is here that the thickness of the particle structure is determined. Supporting the first part of the sieve thus makes it possible to avoid the influence of parasitic phenomena on the thickness of the particle structure.

The first support element improves in particular the uniformity of the thickness over the width of the sieve. Indeed, the sieve is typically maintained laterally by a reinforcing structure that allows it to be stretched, it is more likely to deform towards the middle than on its edges, resulting that, without the first support element, the particle structure tends to be thicker in the middle.

The first support member allows the first surface of the sieve is, on the first portion of the sieve, substantially parallel to the first squeegee.

The first support element is arranged to stretch the first portion of the sieve. The first element of support has the primary function of locally tightening the sieve. The first support member exerts pressure on the screen. Preferably, this pressure has a horizontal component.

The first part of the sieve is preferably the part of the sieve on which the particles are at the moment when they are scraped by the first squeegee. It usually extends from one side to the other of the sieve. If the sieve is cylindrical, the first part of the sieve may for example correspond to an angle of less than 5 degrees, preferably less than 2 degrees.

Preferably, the first scraper comprises a scraping part which is a part of the first scraper intended to be in contact with the particles. In particular, the scraping part may comprise a scraping line, which is preferably a line where the first scraper imposes the thickness of the particle structure, and which is preferably rectilinear and essentially perpendicular to the direction of movement of the first part of the sieve. It is usually the line of the first scraper that is closest to the first surface.

Preferably, there is a plane, called foreground, which comprises the scraping line and which is perpendicular to the first surface at the first scraper. The first support element is arranged to support the sieve in the foreground.

Preferably, the first support member comprises a contact portion which is in mechanical contact with the screen. Preferably the contact portion comprises a contact line which is in mechanical contact with the screen and which is perpendicular to the direction of movement of the particle structure on the first portion of the screen.

The first surface is preferably convex at the first scraper. The second surface is preferably concave at the first support member.

The first scraper is preferably located at a non-zero distance from the first surface, this distance determining the thickness of the particle structure which remains on the first surface after scraping. This distance can be for example controlled by a gauge located between the sieve and the first squeegee.

The first scraper may for example comprise a blade, a roller or any other device. If it comprises a blade, it is preferably inclined relative to the first plane. The first scraper preferably extends from one side to the other of the screen at the first portion of the screen. In other words, it preferably extends over the entire width of the sieve at the first portion of the sieve. Preferably, in the particle structure formed on the first surface of the sieve, the particles are not chemically bonded together. The particle structure is preferably a layer of particles. Preferably, the particles are electrically neutral, that is to say devoid of electric charge.

As part of the present document, a screen is a porous media (for example the screen may have through holes in which a gas can pass). Preferably, the first surface is impenetrable by the particles (i.e. the particles remain locked against said first surface and do not penetrate the screen). The device is preferably designed so that permanently at least 90% of the second surface of the sieve is free of any blockage. This allows the holes to be clear over a large part of the second surface of the sieve.

The screen preferably comprises a sheet of material. Preferably, the screen is flexible but is stretched laterally. The screen forms a means of particle transport since the first surface displaces the particle structure in a direction parallel to its tangent.

The movement of the first surface makes it possible to advance the particle structure, preferably in a direction locally parallel to the first surface. Preferably, the second surface moves along with the first surface. This movement is preferably a rotation.

Preferably, the screen has a convex surface, for example a cylinder, at least partially delimiting an interior space. Preferably, the interior space corresponds to the second side of the sieve.

Preferably, the screen has a section which is a curve h, so as to form a conveyor belt to have a continuous handling method. For example, the screen may be cylindrical. Its axis of rotation is then preferably in the foreground. This closed curve further allows the internal volume of the sieve to be depressed by suction means so as to hold the particles on the first surface. The particle structure is preferably continuous on the first part of the sieve. Indeed, it is preferred that a continuous structure is formed upstream of the scraper, and that eventually parts of this structure is removed downstream of the scraper.

The device preferably comprises a feed element arranged to feed particles to the first surface.

The first surface is typically an outer surface of the screen and the second surface is typically an inner surface of the screen.

In one embodiment, the first support member is directly opposite the first squeegee relative to the sieve, particularly with respect to the first portion of the sieve.

For example, the contact line may be in the foreground. This allows a particularly efficient mechanical support. It is also possible, while remaining within the scope of the invention, for the first support element to comprise two parts located on either side of the first plane but arranged to support the first portion of the sieve in the first plane.

Preferably, the first support member is permanently directly opposite the first squeegee relative to the sieve. For example, if the first scraper is fixed, the first support element too; and if the first scraper moves, the first support member moves simultaneously on the other side of the screen so as to stay directly opposite the first scraper with respect to the screen.

In one embodiment, the first support member extends from one side to the other of the sieve at the first portion of the sieve. In other words, it preferably extends over the entire width of the sieve at the first portion of the sieve.

In one embodiment, the first scraper comprises a scraping part intended to be in contact with the particles, the device being arranged so that the scraping part can be set in motion in a direction opposite to the direction of movement. of the particle structure on the first part of the sieve. This allows to lift the particles that do not pass between the first surface and the first scraper. Thus, this fluidifies the particle powder, which allows it to spread more easily because it forms fewer agglomerates difficult to break. This movement of the scraping part is particularly easy when the first scraper is cylindrical, in which case it is rotated, but can be considered with other forms of scraper.

Preferably, the device according to the invention comprises a motor for moving the first scraper, so as to obtain this movement of the scraping part.

In one embodiment, the first scraper is a cylinder. Preferably, the axis of this cylinder is parallel to the scraping line. Preferably, the axis of this cylinder is in the foreground. A cylinder makes it easier to spread the powder than a blade.

In one embodiment, the first support member comprises a support cylinder. Preferably, the axis of this cylinder is parallel to the line of contact.

In one embodiment, the support cylinder is arranged to be rotated by the sieve.

In one embodiment, the device further comprises suction means arranged to maintain the particles on the first surface. The particles are held on the first surface during at least a portion of the movement of the first surface. In particular, the particles are preferentially held on the first surface during scraping by the first scraper.

The suction means preferably generates a sub-pressure on the side of the second surface of the sieve relative to the pressure prevailing on the side of the first surface of the sieve, on at least a portion of the sieve. Preferably, the interior volume of the sieve is closed laterally, so as to prevent a passage of gas at the lateral ends. Preferably, the suction means is at least partially located on the second side of the screen.

In one embodiment, the device further comprises a second scraper located on the first side of the sieve and arranged to scrape the particle structure on a second portion of the sieve, and

- A second support element located on the second side of the sieve and arranged to support the second portion of the sieve.

The second portion of the sieve is different from the first portion of the sieve.

Preferably, the second support element has the same characteristics and the same arrangement as the first support element. Preferably, the second scraper has the same characteristics and the same arrangement as the first scraper.

If the device comprises two scrapers, the feed member is preferably arranged to feed the first surface between the two scrapers. The reservoir is preferably located between the two scrapers and may be partially delimited by them.

The presence of two scrapers and two support elements allows to reverse the direction of rotation of the sieve while keeping the effect of scraping and support.

The device according to the invention is preferably symmetrical in a vertical plane passing through its axis of rotation.

In one embodiment, the device comprises a blower arranged to blow or expel a gas through the screen in a particle tank.

As part of this document, a blower is any device capable of generating a flow of gas, preferably by ejection.

The flow of gas generated by the blower, and passing through the sieve, sets in motion the particles present in the tank. Thus, the blower makes it possible to thin the powder of particles in the tank. This allows for example to avoid the formation of bridges that prevents the fluid flow of particles. It also makes scraping easier and more effective.

Preferably, the reservoir is at least partially defined by the first scraper. The reservoir may also be partially delimited by a part of the first surface, by the second scraper and / or by walls arranged to retain the particles. The reservoir is a part of the device in which the particles are provided, preferably by a feed member. They are in reserve in the tank. The reservoir is typically upstream of the scraper. The feed element may be part of the tank.

The tank is located on the first side of the sieve. The reservoir is preferably located above the sieve.

In one embodiment, a wall of the tank is at least partially formed by a portion of the screen, in particular by a portion of the first surface of the screen.

In one embodiment, the blower comprises a purge nozzle located on the second side of the screen.

The purge nozzle allows to blow gas through the sieve.

In one embodiment, the blower comprises a first zone located on the second side of the screen and overpressure relative to the tank. The pressure difference between the first zone and the reservoir generates a breath through the sieve, from the first zone to the reservoir.

In one embodiment, the device comprises an ejection device arranged to eject the particles from the first surface, preferably so as to repel the sieve particles.

The ejection device may for example blow gas or send a sound wave to the sieve, which passes through the sieve and carries particles. Preferably, the ejection device blows the gas, or sends the sound wave, perpendicular to the surface of the sieve. The ejection device is preferably arranged to eject the particles downwards or in any other direction (eg horizontal) from the first surface of the sieve.

In one embodiment, the ejection device is located on the second side of the screen and is arranged to generate a flow of transport fluid that passes only predetermined portions of the first surface of the screen.

For example, the ejection device may comprise a series of ejection orifices, each orifice ejecting an element of the transport fluid stream, which is preferably perpendicular to the first portion of the sieve. Preferably, he It is possible to control which ports eject from the transport fluid stream, for example through a valve system. The orifices are preferably arranged in staggered rows.

The invention further relates to a three-dimensional printing system comprising at least once the device according to one of the embodiments of the invention, and an agglomeration means.

Preferably, the system comprises means for moving the screen relative to a three-dimensional printing structure.

The three-dimensional printing is one of the possible applications of the device according to the invention. It can for example be used in the system described in the international patent application PCT / EP2017 / 071039. It can also be used, for example, in a powder bed system, in particular a powder bed additive manufacturing system, as in an SLS system (selective laser sintering) where the device can be used as a cover doctor (recoater in English). In such a system, the function of the device according to the invention may be to deposit a layer of powder on the structure being printed. It is also possible to use it in a screen printing process. In screen printing, it allows in particular to print digital images; to handle powders (dry inks); and print reliefs on different substrates for any type of application.

The sintering means makes it possible to adhere at least a portion of the deposited particles, for example by ejection, to a three-dimensional printing structure, so that these particles are integrated in this three-dimensional printing structure. In the context of the present document, an agglomeration of particles is an attachment together of said particles. Agglomeration is preferentially selective, in that inert particles are not agglomerated. Agglomeration may comprise at least one of the following: heat treatment, sintering, melting, glue application, binder application, or ultrasonic welding. For example, the agglomeration means may comprise at least one of: a furnace, a laser, an electron beam, a laser equipped with a scanning system for ability to heat the entire stratum, a halogen lamp, inductive heating, microwave heating, an ion beam, a local or uniform chemical reaction. Agglomeration can be carried out uniformly line by line, sweeping in one direction with a beam heating the material along a line.

The invention furthermore relates to a method for handling particles comprising the steps of:

Provide a device according to one of the embodiments of the invention,

• provide particles on the first surface,

• move the particles to the first part of the sieve, and

• scrape the particles.

The supply of particles on the first surface precedes scraping. In other words, the particles are provided on the first surface and then moved to the first portion of the screen where they are scraped.

The invention further relates to a three-dimensional printing method comprising, in this order:

The particle manipulation method described above,

• ejection of particles from at least some parts of the particle structure, and

An agglomeration of said particles.

For example, the particles are provided on the first surface, then scraped by the first scraper, and some are ejected by the ejection device. This ejection deposits them on a first substrate or a three-dimensional printing structure where they are agglomerated thanks to agglomeration means.

According to a second aspect, the invention proposes a device for manipulating particles and comprising:

A screen having a first surface on which a particle structure can be formed, the first surface being arranged to be set in motion,

• a reservoir of particles and

A blower arranged to blow a gas through the screen in the tank. The movement of fluid generated by the blower, and passing through the sieve, sets in motion the particles present in the tank. Thus, the blower makes it possible to thin the powder of particles in the tank. This fluidification allows the particles to spread better and do not form blocks. This makes it possible to obtain a more regular particle structure.

Preferably, the blower is below the tank, which allows the screen prevents particles from falling into the blower.

The blower may be combined with one or more of the elements presented in this document, in particular the first and / or second scraper, the first and / or second support element, the suction means, the ejection device and / or the agglomeration means, whatever the arrangement of said element (s).

According to different embodiments, which can be taken together or separately:

- The device comprises a first scraper located on a first side of the sieve and arranged to scrape the particle structure on a first portion of the sieve.

The device comprises suction means arranged to hold the particles on the first surface.

The device comprises an ejection device arranged to eject the particles from the first surface.

The ejection device is located on the second side of the screen and is arranged to generate a flow of transport fluid that passes only predetermined portions of the first surface of the screen.

- A tank wall is at least partially formed by a portion of the screen.

- The blower includes a purge nozzle located opposite the tank relative to the screen. In other words, the purge nozzle is on the second side of the screen. The purge nozzle allows gas to be blown through the screen.

- The blower comprises a first zone located opposite the tank relative to the screen and overpressure relative to the tank. In other words, the first zone is on the second side of the sieve. The invention further provides a three-dimensional printing system comprising at least once the device according to one embodiment of the invention, and a sintering means.

The invention furthermore proposes a method for handling particles comprising the steps of:

Provide a device according to one of the embodiments of the invention,

• supply particles to the reservoir,

• blow a gas through the sieve into the particles in the tank.

Brief description of the figures

Other features and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended figures in which:

FIG. 1 illustrates a sectional view of a part of a device for handling particles according to one embodiment of the invention,

FIG. 2 illustrates a device for manipulating particles according to one embodiment of the invention,

FIG. 3 illustrates a sectional view of a device for handling particles according to one embodiment of the invention,

FIG. 4 illustrates a system comprising at least two devices for manipulating particles according to one embodiment of the invention,

FIG. 5 illustrates a system comprising at least two devices for manipulating particles according to one embodiment of the invention,

FIG. 6 illustrates a sectional view of a part of a device for handling particles according to one embodiment of the invention, and

- Figure 7 illustrates a sectional view of a portion of a device for handling particles according to one embodiment of the invention. Embodiments of the invention

The present invention is described with particular embodiments and references to figures but the invention is not limited by them. The drawings or figures described are only schematic and are not limiting.

In the context of this document, the terms "first" and "second" serve only to differentiate the different elements and do not imply order between these elements.

In the figures, identical or similar elements may bear the same references.

Although the particles are shown as being spherical, the present invention may relate to particles of any shape. In addition, the size of the particles and the particle structure is generally exaggerated in the figures.

According to a first aspect of the invention, the device comprises a first scraper and a first support element. The first scraper and the first support element are illustrated in FIGS. 1, 2, 3 and 4. According to a second aspect of the invention, the device comprises a reservoir and a blower. The reservoir and the blower are illustrated in FIGS. 2, 3, 5 and 6. The elements illustrated in all the figures of the present document are compatible with both aspects of the invention. In addition, a feature presented in one embodiment of one of the two aspects may be present in one embodiment of the other of the two aspects of the invention.

Figure 1 illustrates a sectional view of a portion of a device 1 for handling particles according to one embodiment of the invention. The device 10 comprises a screen 10, a first scraper 86 and a first support element 88.

The screen 10 has a first surface 1 1 located on a first side 201 of the screen 10 and a second surface 12, opposite the first surface 1 1 and located on a second side 202 of the sieve 10 opposite the first side 202. The sieve 10 can be set in motion. In particular, it can be rotated, for example according to a closed curve of any shape. The first side 202 is preferably underpressure with respect to the first side 201, by means of suction means, so as to now the particles on the surface of the sieve 10 by suction.

A structure 30 of particles may be formed on the first surface 1 1. It moves with the first surface January 1. In general, it moves in a direction that is parallel to the tangent to the first surface 1 1. This direction is illustrated by the arrow 203 at the first scraper 86. The particle structure 30 is scraped by the first scraper 86 , so that it is generally thicker upstream of the first scraper 86 downstream thereof. The portion of the sieve 10 on which scraping is performed may be referred to as the first portion 51 of the sieve. It is preferably essentially a rectilinear line tangent to the first surface 1 1 and perpendicular to the direction 203 of the movement of the structure 30.

The first scraper 86 is located on the first side 201 of the screen 10 at a distance 206 from the screen. The first scraper 86 includes a scraper portion 187 which is intended to be in contact with the particles. It can also be called the first scraping part. Preferably, the scraping portion 187 comprises a scraping line 186 perpendicular to the plane of FIG.

The first support element 88 is located on the second side 202 of the screen 10, preferably directly opposite the first scraper 86.

In general, there is a plane, called the first plane 150, which comprises the scraping line 186 and which is perpendicular to the first surface 1 1 at the first scraper 86.

Preferably, the first support element 88 comprises a contact portion 188 which is in mechanical contact with the screen 10, in particular with the second surface 12. This contact part may for example be a line parallel to the line The contact portion 188 is preferably at least partially in the first plane 150.

According to one embodiment of the invention, the device 1 is arranged so that the scraping part 187 can be set in motion in a direction 204 opposite the direction 203 of movement of the particle structure on the first part 51 sieve 10. FIG. 2 illustrates a device 1 for manipulating particles according to one embodiment of the invention.

In the embodiment illustrated in Figure 2, the screen 10 is cylindrical and the first support member 88 is a support cylinder. The axis of rotation of the screen and that of the first support element 88 are parallel and in the first plane 150. The rotation of the screen 10 causes the rotation of the first support element 88 by contact.

FIG. 2 illustrates that the device 1 may comprise a reservoir 80 of particles, one wall 81 of which is formed by a part of the screen 10. Another wall of the reservoir 80 is formed by the first scraper 86. The device 1 comprises in part in addition to a blower arranged to blow a gas through the screen 10 in a tank 80. The blower may comprise for example a purge nozzle 91.

FIG. 2 also illustrates a width 205 of the screen 10, which is a dimension of the screen perpendicular to its direction of movement 203. It can be seen that the first scraper 86 and the first support element 88 extend on one side. to the other of the sieve 10.

[0091] Figure 3 illustrates a sectional view of a device 1 for handling particles according to one embodiment of the invention. In the embodiment illustrated in Figure 3, the screen 10, the first scraper 86 and the first support member 88 are cylindrical. Their axes of rotation are parallel and in the foreground 150.

In the embodiment illustrated in FIG. 3, the device 1 further comprises a second scraper 87 located on the first side 201 of the screen 10 and arranged to scrape the particle structure 30 on a second portion 52 of the screen 10 and a second support element 89 located on the second side 202 of the screen 10 and arranged to support the second portion 52 of the screen 10. The second scraper 87 and the second support element 89 are cylindrical, but they could have another shape while remaining in the context of the present invention. Their axes of rotation are parallel to that of the screen 10 and are in a second plane 152. The second plane 152 is defined with respect to the second scraper 87 as the first plane 150 is defined relative to the first scraper 86. A second scraping portion 189 is defined with respect to the second scraper 87 as the first scraping portion 187 is defined with respect to the first scraper 86.

The second scraper 87 and the second support element 89 serve in particular to be able to reverse the direction of rotation of the screen 10 while retaining the characteristics of the device 1. The second scraper 87 may also serve as a wall for the reservoir 80.

The rotation of the screen 10 causes the rotation of the first support element 88 and the second support element 89 by contact.

The first scraper 86 is preferably in rotation, so that the scraping part 187 describes a movement in the direction 204 opposite the direction 203 of movement of the particle structure on the first part 51 of the screen 10. This rotation is preferably driven by a motor. This rotation makes it possible to return particles to the reservoir 80. The device 1 is preferably arranged to be able to also rotate the first scraper 86 in the other direction.

The second scraper 87 is preferably rotated, so as to bring particles to the reservoir 80. This rotation is preferably driven by a motor.

In the embodiment illustrated in Figure 3, the device 1 comprises a blower comprising a first zone 92 located on the second side 202 of the screen 10 and overpressure relative to the tank 80. The blower sends gas through the part of the sieve 81 which forms a wall of the tank 80. The tank 80 is preferably situated above the sieve 10, so that the particles tend to go on the first surface 11 of the sieve 10 thanks to the gravity, despite the blower.

The blower of the device 1 illustrated in FIG. 3 could comprise the purge nozzle 91 illustrated in FIG. 2, in addition to the first zone 92 under excess pressure.

In the embodiment illustrated in FIG. 3, the device 1 also comprises a feed element 90. Preferably, the blower also blows in the feed element 90. Preferably, the device 1 also comprises a second zone 94, in depression relative to the pressure prevailing on the first side 201 of the screen 10 by means of suction means. This depression makes it possible to maintain the particles on the screen 10. The first 92 and the second 94 zones can be separated by a separation wall 93 hermetic to gas.

In the embodiment illustrated in FIG. 3, the device 1 also comprises an ejection device 121 arranged to eject the particles from the first surface 11 of the screen 10.

The device 1 may for example operate in the following manner. The supply element 90 supplies the reservoir 80 with particles. The particle structure is formed in the reservoir 80 and is driven by the rotation of the screen to form a layer on the first surface 1 1. Upon reaching the first scraper 86, the particles are compacted and scraped and some remain in the reservoir 80. The particles that continue the movement form a continuous portion 31 of the structure 30, that is to say an even layer of particles. Upon reaching the ejection device 121, some parts of the particle structure 30 are ejected, for example to form part of a particle stratum. The portions of the particle structure that are not ejected remain on the first surface 11 and form discontinuous portions 32 of the structure 30. These portions pass between the second scraper 87 and the first surface 11 and are reintegrated into the surfaces. particles 80. The blower is particularly interesting to take off these particles from the first surface 1 1 so that the structure 30 formed again on these parts of the first surface 1 1 is as regular as possible and does not keep track of previous ejections .

Figures 4 and 5 illustrate a system 100 comprising at least two devices 1a, 1b for handling particles according to one embodiment of the invention. This system can for example be used for three-dimensional printing. It is possible, while remaining within the scope of the invention, that the system 100 comprises more than two devices 1 according to the invention. The screens 10a, 10b are arranged parallel to each other, preferably with their axis in the same horizontal plane. In the illustration of FIGS. 4 and 5, the system 100 is in printing a three-dimensional printing structure 72 which may comprise particles already agglomerated or not yet agglomerated.

Figure 4 illustrates that the scrapers 86a, 86b, 87a, 87b can be inclined relative to the first plane, while the support elements 88a, 88b 89a, 89b are in the foreground.

Preferably, the particles 3a disposed by the first device 1a are particles 3a of a first type, for example capable of being agglomerated by a specific method. Preferably, the particles 3b disposed by the second device 1b are particles 3b of a second type, for example not capable of being agglomerated by this determined method.

Preferably, the sieves 10a, 10b rotate by maintaining fixed their axis of rotation when a stratum 35 is deposited, and a first substrate 60, which serves as a support for the three-dimensional printing structure 72 advances in a direction or in the other. It is also possible, while remaining within the scope of the invention, that the screens 10a, 10b have their axis of rotation which moves parallel to the first substrate 60 and that it is fixed. It is also possible that the screens 10a, 10b and the first substrate 60 move in a coordinated manner.

The ejection devices 121a, 121b are controlled so as to obtain the desired three-dimensional printing structure 72. Preferably, they are controlled so that the layer 35 formed by the particles 3a, 3b deposited by the devices 1a, 1b is continuous, that is to say, has no hole.

When a layer of particles has been deposited, and before depositing the next layer, the sieves 10a, 10b are moved away from the three-dimensional printing structure 72 by a distance preferably equal to the thickness of the film. stratum 35. This allows the next stratum to be deposited. It is possible that successive layers have different thicknesses.

In one embodiment of the invention, the system 100 further comprises at least one compacting roller 141 forming a means for uniformizing the height of the layer of powder deposited on the three-dimensional printing structure. Preferably, the system 100 comprises two uniformizing means, each being located on one side of the screens 10a, 10b. In a mode of embodiment of the invention, the system 100 further comprises at least one agglomeration means 75. Preferably, the system 100 comprises two agglomeration means 75, each being located on one side of the screens 10a, 10b, further that means of standardization.

[0111] Preferably, the system 100 operates as follows.

A bed of particles of the second type 3b, which are not likely to be agglomerated by the process carried out by the agglomeration means 75, is deposited on the first substrate 60. The bed of particles forms the structure of three-dimensional printing 72 starting.

The reservoir 80a is filled with particles of the first type 3a, which are capable of being agglomerated by the process carried out by the agglomeration means 75. The reservoir 80b is filled with particles of the second type 3b.

The screens 10a, 10b each rotate about their axis, causing particles of the tanks 80a, 80b which are maintained on the first surfaces by an air suction, for example by an external fan connected to the internal volumes of the sieve. The air flow of the suction is chosen according to the type of powder. The thickness of the particle layer 3a, 3b on the screen 10 is preferably between 50 μm and 1000 μm. It is determined in particular by the position of the second scrapers 87a, 87b. The thickness of the layer 35 may be different from the thickness of the layer on the screen 10. In fact, the particles of the layer 35 may spread after deposition. It is also possible to vary the thickness of the layer 35 by varying the rotational speed of the screen and / or translation of the three-dimensional printing structure 72.

The sieves 10a, 10b move horizontally in a direction perpendicular to their axis, so as to traverse the three-dimensional printing structure 72, while rotating on themselves. Preferably, the rotation and translation speeds are synchronized so that the relative speed of the closest point of the screen 10 and the three-dimensional printing structure 72 is zero. Thus, the particles have no tangential velocity sieve during the transfer, which allows a deposit of greater accuracy. The particles that have not been deposited back to the tanks 80a, 80b and can be used thereafter.

Preferably, once the stratum 35 is deposited, it is standardized by the compacting roller 141, then agglomerated by the agglomeration means 75 so as to integrate the three-dimensional printing structure 72. The following stratum 35 is then filed.

It is possible that the next layer 35 is deposited on the return path with respect to the layer that has just been integrated into the three-dimensional printing structure 72. For example, the deposition of the layers (as well as the compaction and agglomeration) can be from right to left, and from left to right. In this case, it is preferred that the system comprises two uniformization means and two agglomeration means 75 as illustrated in FIG. 16.

FIG. 6 illustrates a sectional view of a part of a device 1 for handling particles according to one embodiment of the invention. Figure 7 illustrates a sectional view of a portion of a device 1 for handling particles according to one embodiment of the invention. In the second aspect of the invention, the device 1 does not necessarily include a scraper, and if it includes a scraper, it does not necessarily include a support member as described herein. Device 1 comprises a screen 10 having a first surface 11 on which a particle structure 30 may be formed. The sieve is preferably similar to that described with reference to any one of Figures 1 to 5. The device 1 also comprises a blower arranged to blow a gas through the sieve 10 in a tank 80 of particles. The blower may for example comprise a purge nozzle 91 situated opposite the reservoir 80 with respect to the screen 10, or a first zone 92 situated opposite the reservoir 80 with respect to the screen 10 and in excess pressure with respect to the reservoir 80.

In other words, the invention relates to a device 1 for manipulating particles. The device 1 comprises a rotating screen 10 on which a particle structure 30 may be formed. According to a first aspect of the invention, the device 1 comprises at least one scraper 86, 87 and at least one support element 88, 89 supporting the screen 10 at the scraper 86, 87. According to a second In one aspect of the invention, the device 1 comprises a reservoir 80 of particles and a blower, preferably located inside the screen 10 and under the tank 80, and blowing a gas to lift the particles present in the reservoir 80.

The various embodiments and aspects of the invention are combinable with the system described in the international patent application PCT / EP2017 / 071039.

The present invention has been described in relation to specific embodiments, which have a purely illustrative value and should not be considered as limiting. In general, the present invention is not limited to the examples illustrated and / or described above. The use of the verbs "to understand", "to include", "to include", or any other variant, as well as their conjugations, can in no way exclude the presence of elements other than those mentioned. The use of the indefinite article "a", "an", or the definite article "the", "the" or "", to introduce an element does not exclude the presence of a plurality of these elements . The reference numerals in the claims do not limit their scope.

Claims

claims

Apparatus (1) for handling particles comprising:

A screen (10) having a first surface (1 1) on which a structure

(30) of particles can be formed, the first surface (1 1) being arranged to be set in motion, and

A first scraper (86) located at a first side (201) of the sieve (10), at a distance (206) which is non-zero from the first surface (1 1), and arranged to scrape the structure (30) of particles on a first portion (51) of the sieve (10), characterized in that it comprises a first support member (88) located on a second side (202) of the sieve (10) and arranged to support the first part (51) sieve (10), the second side (202) of the sieve (10) and the first side (201) of the sieve (10) being separated by the sieve (10),

the first surface (1 1) being arranged to be moved to move the particle structure (30) in a direction parallel to the tangent to the first surface (1 1).

2. Device (1) according to claim 1, further comprising a suction means arranged to maintain the particles on the first surface (1 1).

3. Device (1) according to any one of the preceding claims, wherein the first support member (88) is arranged to tension the first portion (51) of the screen (10).

4. Device (1) according to any one of the preceding claims, wherein the first support member (88) extends from one side to the other of the sieve (10) at the first portion (51). sieve (10).

5. Device (1) according to any one of the preceding claims, wherein the first scraper (86) comprises a scraping part (187) intended to be in contact with the particles, the device (1) being arranged so that the part of scraping (187) can be set in motion in a direction (204) opposite to the direction (203) of movement of the particle structure on the first portion (51) of the screen (10).

6. Device (1) according to any one of the preceding claims, wherein the first scraper (86) is a cylinder.

7. Device (1) according to any one of the preceding claims, wherein the first support member (88) comprises a support cylinder.

8. Device (1) according to the preceding claim, wherein the support cylinder is arranged to be rotated by the screen (10).

The device (1) according to any one of the preceding claims, further comprising:

- a second scraper (87) located on the first side (201) of the sieve (10) and arranged to scrape the structure (30) of particles on a second portion (52) of the sieve (10), and

a second support element (89) located on the second side (202) of the sieve

(10) and arranged to support the second portion (52) of the screen (10).

10. Device (1) according to any one of the preceding claims, comprising a blower arranged to expel a gas through the screen (10) in a tank (80) of particles.

1 1. Device (1) according to any one of the preceding claims, further comprising an ejection device (121) arranged to eject the particles of the first surface (1 1).

12. Device (1) according to the preceding claim, wherein the ejection device (121) is located on the second side (202) of the screen (10) and is arranged to generating a transport fluid stream that passes only predetermined portions of the first surface (11) of the screen (10).

13. A three-dimensional printing system comprising at least once the device (1) according to any one of the preceding claims, and an agglomeration means (75).

14. A method of handling particles comprising the steps of:

• providing a device (1) according to any one of claims 1 to 12, · providing particles on the first surface (1 1),

Moving the particles to the first portion (51) of the sieve (10), and

• scrape particles

wherein the supply of particles to the first surface precedes scraping.

15. A three-dimensional printing method comprising, in this order:

The process according to the preceding claim,

• ejection of particles from at least some parts of the particle structure (30), and

An agglomeration of said particles.